Science : Ch 11 – The Human Eye and the Colourful World

A clear sky appears blue, because:

The danger signals installed at the top of tall buildings are red in colour. These can be easily seen from a distance because among all other colours, the red light:

Which of the following phenomena contributes signifcantly to the reddish appearance of the sun at sunrise or sunset?

The bluish colour of water in deep sea is due to:

The absorption of light by a molecule depends on the

Power of a lens is the measure of the degree of

Arpit remarked that he has seen wavering of objects when seen through a stream of hot air rising above a tandoor or a fire. He said that the air just above the fire becomes hotter than the air further higher up. He further said that this wavering can also be seen in the earth’s atmosphere as the earth’s atmosphere is not evenly distributed ,What is the total time diference on duration of day on earth?

Why don’t planets twinkle?

When a fine beam of sunlight enters a smoke filled room, smoke particles become visible due to scattering of light by these particles

When sunlight passes through a canopy of a dense forest, tiny water droplets in the water scatter light.This is an example of

Why is red used as the stopping light at traffic signals?

The defect in a person can see nearby objects but not far away objects

Astigmatism can be corrected

The SI unit of Power of a lens is

The colour of scattered light depends on the